Tape Measure Lock Flexure for Curved Linkage Actuation
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Solution Overview
Problem
Conventional tape measure devices face challenges in optimizing form-factor utilization due to the constraints imposed by the location of the locking mechanism, often requiring rigid linkages and push-rods for actuation, which can be cumbersome and inefficient.
Innovation Solution
A flexible metal or plastic lock linkage flexure is used within the tape measure device, allowing translational force transmission without a straight line path, supported by a curved travel pathway and optionally assisted by a secondary spring for state restoration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid linkages and push-rods are used to transmit actuation force from the external button to the locking mechanism, then the locking mechanism can be actuated reliably, but the device complexity and form-factor utilization are worsened due to the need for straight line paths and additional structural components
Solution Approach 1:
The patent applies a flexible cable linkage instead of rigid linkages and push-rods to transmit actuation force. The flexible cable can bend and follow curved paths within the housing, eliminating the need for straight line paths and reducing the number of structural components required, thereby simplifying the overall device complexity while maintaining reliable actuation of the locking mechanism.
Solution Approach 2:
The flexible cable linkage allows for curved paths of force transmission within the housing. This curvature enables the cable to navigate around other components and reach the locking mechanism from the external button location without requiring rigid straight-line connections, thus reducing device complexity while preserving actuation reliability.
2Ease of operation
If rigid linkages are used to connect the external button to the locking mechanism, then the actuation path is straightforward, but the form-factor utilization is worsened due to space requirements for straight line paths
Solution Approach 1:
The flexible cable linkage can be routed through curved pathways within the housing, allowing the actuation force to be transmitted from the external button to the locking mechanism without requiring straight line paths. This reduces the area occupied by the linkage system within the housing while maintaining ease of operation.
Solution Approach 2:
The flexible cable linkage transitions from requiring three-dimensional straight line paths to utilizing two-dimensional curved surfaces within the housing. This dimensional change allows the cable to follow the contours of the housing interior, reducing the overall space required for the actuation mechanism while preserving operational simplicity.
3Area of stationary object
If the locking mechanism is positioned out of direct line of effect from the external button, then the device form-factor is optimized, but the actuation efficiency is worsened with conventional rigid linkages
Solution Approach 1:
The flexible cable linkage efficiently transmits actuation force over curved paths and around corners within the housing, maintaining high actuation efficiency even when the locking mechanism is positioned out of direct line of effect from the external button. This allows for optimized device form-factor without sacrificing productivity.
Solution Approach 2:
The flexible cable acts as an intermediary that efficiently bridges the gap between the external button and the locking mechanism positioned out of direct line of effect. The cable's flexibility allows it to navigate complex spatial relationships while maintaining effective force transmission, thus preserving actuation efficiency in compact form-factors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The flexible lock linkage enables efficient and low-profile actuation of the locking mechanism, allowing for user-friendly and removable/replaceable operation, while maintaining structural integrity and ease of use.
Implementation Method 1
a lock linkage flexure that transmits translational force but without requiring a straight line path to do so is supporting in the linkage travel pathway
Implementation Method 2
A secondary spring may be used to restore state when the user release the locking mechanism
Data Source
AI summary
A tape measure device comprising a housing at includes a reel that support a tape measure, a linkage travel pathway, and an external locking mechanism configured to be engaged by a user to lock the tape measure at some extended position. According to this disclosure, a lock linkage flexure that transmits translational force but without requiring a straight line path to do so is supporting in the linkage travel pathway. In one embodiment, the flexure is implemented as a metal linkage that is constrained in the curved travel pathway and maintains a low profile as it is actuated by the lock action (whether in an auto-lock configuration or fixed lock format). The metal linkage travels through the define pathway to guide and direct the motion.